(a) Field of the Invention
The invention relates to an oscillator, particularly to an oscillator with power saving features and the method thereof.
(b) Description of the Related Art
FIG. 1 is a schematic diagram of a conventional oscillator 100, including an oscillation unit 101 and a crystal circuit 102. The oscillation unit 101 includes an inverter In and a resistor R. The crystal circuit 102 includes a piezoelectric quartz crystal Pi and two capacitors C1, C2.
The oscillation unit 101 generates an oscillating signal Xout by the piezoelectric quartz crystal Pi and capacitors C1, C2. In order to reach a target frequency rapidly during initiation, a large oscillation current (e.g., 3˜6 mA, even larger) is applied to the oscillator 100. During the course of oscillator operation, the oscillation unit 101 and the capacitors C1, C2 generate negative resistance to counteract the equivalent series resistance (ESR) of the piezoelectric quartz crystal Pi to sustain the oscillation. However, the inverter In consistently consumes the relatively large first current during operation, which leads to unnecessary power consumption.